The downlink of a WCDMA (Wideband Code Division Multiple Access) system uses an HSDPA (High Speed Downlink Packet Access) technology to provide high-speed downlink transmission. Relays are introduced into the WCDMA system, which can provide more reliable transmission and higher system throughput. This effectively improves coverage of the system. Because physical locations of multiple relays are far away from each other, channels from a base station to different relays are uncorrelated. Two relays with good orthogonality are selected from multiple relays to perform MU-MIMO (Multi-User Multiple-Input Multiple-Output) transmission, which may use multiple antennas of the base station to achieve higher throughput performance.
In the prior art, when the base station uses the MU-MIMO technology to serve two relays simultaneously, the base station uses HS-SCCH (Shared Control Channel for HS-DSCH) Type 3 for transmitting a single data block. It uses two HS-SCCHs to respectively transmit control channel information of HS-PDSCHs of the two MU-MIMO relays. To enable a specified user to perform reception, the information of the HS-SCCH is scrambled by using an identifier of the specified user. Two HS-SCCHs use respective relay identifiers for scrambling. The two relays descramble the control channel information after receiving respective control channel information.
When MU-MIMO transmission from the base station to two relays is performed, the base station may use two independent HS-SCCHs to respectively transmit control channel information of the two relays. However, on the one hand, the control channel information of the two relays includes the same channelization code bits, and using two HS-SCCHs may cause additional overheads such as a CRC (Cyclic Redundancy Check, cyclic redundancy check) code and a message header; on the other hand, every pair of MU-MIMO relays uses two HS-SCCHs, which may result in an exponential increase of used HS-SCCHs; if two groups of MU-MIMO relays are scheduled, four HS-SCCHs are used. In this case, control channels are all occupied but there are still remaining data code channels, which results in a big waste of resources and a decrease of throughput. The case of scheduling one group of MU-MIMO relays is similar.